a researcher is investigating the effectiveness of a new study-skills training program for elementary school children.

a researcher is investigating the effectiveness of a new study-skills training program for elementary school children. A sample of n=25 third grade children is selected to participate, and each child is given a standardized achievement test at the end of the year. For the regular population of third-grade children, scores on the test , from a normal ditrubution with a mean of 149 and a standard deviation of 25. The mean sample is 157.